When the plane crashed on the island it split into multiple pieces in midair. All the main characters from the fuselage assumed that the tail end passengers had died but in season 2 it was revealed that they survived just as they had. Since their group had children in it the others attacked them on their first night and again a few weeks later, most of the people were either captured or killed. The few remaining people made their way across the island to the main group but even after that all but one of them ended up being killed.
*WARNING - THE FOLLOWING INFORMATION MAY CONTAIN SPOILERS IF YOU ARE NOT CAUGHT UP IN THE SHOW.
Ana Lucia Cortez - Ex - police office and leader of the tail section of the plane. After multiple attacks on her group and seeing countless people killed she becomes very distrusting of everyone and finds it hard to assimilate into the main castaways group. While traveling across the island she accidently shoots and kills one of the castaways from Jack's group thinking she was an other, this ostracizes her and keeps her from ever truly joining the main group. She is later killed by Michael Dawson when he betrays the group to help the hostiles.
Mr. Eko - Eko was a drug dealer who became a priest after his brother had died. While on the island he was very spiritual which made him and locke become close allies when they met, until Locke lost his faith for a brief while and they became enemies. It is later revealed that the plane that Eko's brother was one had crashed on this very same island years prior to their arrival. Mr. Eko was the last of the tail-end survivors to be killed on the island.
Elizabeth Smith - Referred to as Libby, she was a tail-end survivor who became romantically involved with Hugo. Through flashbacks it was revealed that she gave Desmund the boat that brought him to the island and was in the same mental institution as Hurly although they never explained why she was there. She was killed with Ana Lucia by Dawson when he betrays the group
Bernard Nadler - Bernard was a dentist prior to the plane crash and is married to Rose Nadler, a passenger from the fuselage. He is the last living member of the tail - end survivors.